JPH05343639A - Electronic device - Google Patents

Abstract

PURPOSE:To realize an electronic device having a large capacitance part of small leak current, by using crystalline metal oxide as an insulating film, and forming a reaction preventing layer. CONSTITUTION:A reaction preventing layer 9 is formed between an electrode 8 composed of silicon and a crystalline metal oxide, so that the reaction of silicon with crystalline metal oxide can be prevented. Since the insulating film 10 is composed of crystalline metal oxide having grain boundaries, silicon nitride, silicon carbide and fluoride are gradually diffused in the grain boundaries of the crystalline metal oxide, when these components are used for the reaction preventing layer 9. Hence the components existing on the interface between the electrode 8 and the insulating film 10 are remarkably decreased. Thereby the decrease of effective capacitance of the catacitor part does not practically cause trouble, so that an electronic device provided with a capacitor part of large capacitance and small leak current can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component having a capacitor section using a crystalline metal oxide as an insulating film.

[0002]

2. Description of the Related Art Conventionally, in the field of semiconductors, many capacitor parts such as a storage capacitor formed in a memory cell of a memory such as a DRAM and a bypass capacitor connected to the outside of a semiconductor element are incorporated in a circuit. In this case, SiO ₂ is most commonly used as an insulating film for such a capacitor portion. Further, as the semiconductor device has been highly integrated in recent years, there is a demand for a large capacity of the capacitor portion as described above. From such a viewpoint, amorphous materials such as Ta ₂ O ₅ having a much higher dielectric constant than SiO ₂ are used. Attempts have been made to use high quality metal oxides as insulating films.

By the way, such a metal oxide is SiO
_Since it is more unstable than that of ₂ , the reaction between the silicon substrate or polysilicon and the metal oxide occurs when, for example, a silicon substrate or polysilicon is used as the lower electrode and a capacitor portion having the metal oxide as an insulating film is formed thereon. There is a problem that occurs. That is, when the reaction as described above occurs, the oxygen in the metal oxide is insufficient, so that pinholes or the like are generated in the insulating film, the leak current of the insulating film increases, and the reliability is significantly impaired. I will end up.

In view of the above problems, when the metal oxide is used for the insulating film of the capacitor portion, it has been considered to provide a reaction preventive layer between the silicon substrate and the metal oxide. For example, JP-A-2-36559 discloses a semiconductor device in which a reaction preventive layer made of silicon nitride, titanium oxide, or the like is provided between an electrode made of silicon and an insulating film to suppress a leak current in an insulating film of a capacitor. It is disclosed. However, when such a reaction preventive layer is provided, the layer of silicon dioxide produced by the reaction of silicon nitride or silicon and titanium oxide behaves as a low-capacity capacitor adjacent to the insulating film made of metal oxide, There is a problem that the effective capacity of the capacitor part is lowered and the capacity cannot be sufficiently increased.

[0005]

As described above, it has been attempted to increase the capacity of the capacitor section by using an amorphous metal oxide as the insulating film of the capacitor section. In an electronic component having a capacitor portion, the leak current in the insulating film is large and it is difficult to put it into practical use. The present invention solves such a problem, and
It is an object of the present invention to realize an electronic component which has a large capacitance and has a small dc current.

[0006]

According to the present invention, in an electronic component having a capacitor portion having a crystalline metal oxide as an insulating film, at least one of a pair of electrodes opposed to each other through the insulating film is made of silicon. And a transition metal nitride containing at least one selected from the group consisting of silicon nitride, silicon carbide and fluoride or containing less than 20 atm% oxygen is interposed between the electrode made of silicon and the insulating film. It is an electronic component. That is, the electronic component of the present invention uses a crystalline metal oxide as an insulating film of a capacitor part, and further, a reaction preventive layer for preventing a reaction between silicon and the crystalline metal oxide when the capacitor part is formed. It is characterized by the provision of. Hereinafter, such a reaction preventive layer will be described in detail.

When silicon nitride, silicon carbide and fluoride are used in the reaction preventive layer in the present invention, it is desirable that the thickness when the reaction preventive layer is provided is less than 20 angstroms. This is because the components as described above are insulative, so if the reaction preventing layer is provided too thickly, a large amount remains at the interface between the electrode and the insulating film even after these components diffuse into the grain boundaries of the insulating film, This is because the effective reduction in the capacitance of the capacitor may pose a problem. Further, in the present invention, it is more preferable that the thickness of the reaction preventing layer as described above is 10 angstroms or less, and more preferably 5 angstroms or less. Further, in the present invention, the lower limit of the thickness when the reaction preventive layer is provided is not particularly limited, and it is sufficient that the reaction preventive layer can be provided at the interface between the electrode and the insulating film at a minimum thickness. .. In the present invention, the reaction prevention layer does not necessarily have to be uniformly provided at the interface between the electrode and the insulating film, and in some cases, nitrogen, carbon, or fluorine in the reaction prevention layer causes silicon dangling on the electrode surface. It is also possible to simply terminate the bond.

In the present invention, as a method for providing the above-mentioned reaction preventive layer, a sputtering method, a reactive vapor deposition method, C
VD method etc. are mentioned. Further, when the reaction prevention layer is provided between the silicon substrate which will be the lower electrode and the insulating film, the silicon substrate is changed to nitrogen gas, ammonia gas, methane gas, fluorine gas or the like before forming the insulating film on the silicon substrate. The reaction preventive layer can also be provided by exposing. Moreover, according to such a method, the reaction rate between the gas such as nitrogen gas and the silicon substrate tends to be saturated,
It is possible to control the anti-reaction layer to a very thin and uniform thickness.

On the other hand, in the present invention, a transition metal nitride containing less than 20 atm% oxygen may be used in the reaction preventive layer. At this time, when the content of oxygen in the transition metal nitride is 20 atm% or more, a reaction occurs between oxygen in the reaction preventing layer and silicon, silicon dioxide is formed at the interface, and the effective capacitance of the capacitor portion is formed. Since the capacity may decrease, the oxygen content in the transition metal nitride should be 20a.
It is less than tm%. Further, the preferable oxygen content in the transition metal nitride is 10 to 15 atm%. The reason for this is
If the transition metal nitride contains oxygen to this extent,
Even if oxygen is deficient in the insulating film made of a crystalline metal oxide, oxygen is supplemented from the transition metal nitride, and an increase in leak current in the insulating film can be suppressed. In the present invention, such a reaction preventive layer can be obtained by thermally nitriding a transition metal oxide layer formed by, for example, a sputtering method or a CVD method in an atmosphere of nitrogen gas, ammonia gas or the like.

In the present invention, the transition metal nitrides as described above are specifically TaN, NbN, TiN,
ZrN, HfN, YN etc. are mentioned. Further, when a transition metal oxide described below is used for the insulating film of the capacitor part, it is preferable to use the same transition metal nitride as the transition metal oxide for the reaction preventing layer from the viewpoint of interlayer compatibility. desirable.

In the present invention, when the above transition metal nitride is used for the reaction preventive layer, it is desirable that the thickness of the reaction preventive layer is 5 to 100 angstroms. The reason for this is that although the transition metal nitride is electrically conductive,
Since the resistance value is relatively large, if the reaction preventing layer is provided too thick, the resistance between the electrode made of silicon may increase, and conversely, the reaction preventing layer having a thickness of less than 5 angstroms should be provided. Is extremely difficult.

The crystalline metal oxide used for the insulating film in the present invention includes Ta ₂ O ₅ , Nb ₂ O ₅ and TiO _2.
2 , transition metal oxides such as ZrO ₂ , HfO ₂ and Y ₂ O ₃ , perovskite type oxides such as calcium titanate, strontium titanate, bismuth titanate and lead zirconate, and complex oxides thereof. be able to.
However, when the transition metal oxide is used, it is usually necessary to crystallize the transition metal oxide, and for example, after forming the insulating film, the transition metal oxide is 650 to 1000 ° C., 10 to 1 ° C. in a nitrogen atmosphere.
Treatment such as annealing for 20 minutes, preferably 15 to 100 minutes is performed. At this time, the condition of the anneal is limited to the above range because the transition metal oxide is not sufficiently crystallized when the temperature of the anneal is low or the time is short.
This is because if the temperature of the transition metal oxide is high or the time is long, oxygen deficiency or the like may occur in the transition metal oxide. Furthermore, when the reaction preventive layer is provided between the silicon substrate serving as the lower electrode and the insulating film, if the temperature of the anneal is high or the time is long, the silicon substrate serving as the lower electrode and the transition metal oxide are It is not particularly preferable because it may react through the reaction preventive layer. The transition metal oxide is added with a dissimilar metal having a smaller positive charge number in the ionized state than the transition metal, preferably a dissimilar metal having the charge number smaller than the transition metal by 1 to a maximum of about 5 atm%. Good.

In the present invention, a pair of electrodes are formed opposite to each other with the insulating film made of the crystalline metal oxide interposed therebetween to form a capacitor section. At least one of the electrodes is made of silicon such as single crystal silicon or polysilicon, preferably silicon having a specific resistance value of 0.1 Ω · cm or less, and the other electrode is not limited. Specific examples of usable materials other than silicon include Au, Pt, Cu, Ag,
Examples include Pd, Al, W and silicides of transition metals,
Further, in order to improve the adhesiveness with the insulating film, Ti / Au, Ti /
It may be a multilayer electrode of Pt, Ta / Pt, Mo / Au, or the like. Such an electrode can be easily formed by a sputtering method, a vapor deposition method, or the like, and the thickness is preferably 1 μm or less. Further, when the silicon substrate is used as one electrode as it is, it is preferable that it has a thickness of about 0.3 mm in consideration of thermal stress generated during operation.

INDUSTRIAL APPLICABILITY The present invention can be applied to all electronic parts having a capacitor portion such as a storage capacitor and a bypass capacitor in a memory in a circuit. When the present invention is applied to the storage capacitor as described above, Ta ₂ is used as the insulating film of the capacitor section.
It is preferable to use a crystalline metal oxide having a high dielectric constant such as O ₅ or PZT, and when the present invention is applied to a bypass capacitor, Ta ₂ O ₅ , SrTiO ₃ , or B is used.
High frequency band such as iTiO ₃ (100MHz to 10GH
In z), it is desirable to use a crystalline metal oxide having a good frequency characteristic of permittivity and a small temperature coefficient.

[0015]

In the present invention, since the reaction preventive layer is provided between the electrode made of silicon and the insulating film made of crystalline metal oxide, the reaction between the silicon and crystalline metal oxide at the time of forming the capacitor portion is prevented. Can be prevented. Moreover, since the insulating film is made of a crystalline metal oxide having a grain boundary, even if silicon nitride, silicon carbide, or a fluoride is used for the reaction preventive layer, such a component is still present in the grain boundary of the crystalline metal oxide. It is gradually diffused in. Therefore, the above-mentioned components existing at the interface between the electrode and the insulating film are significantly reduced, so that the reduction in the effective capacitance of the capacitor portion is not a practical problem.

When a transition metal nitride containing less than 20 atm% oxygen is used in the reaction preventive layer, oxygen contained in the transition metal nitride causes an increase in leak current. The oxygen deficiency in the insulating film of the part can be compensated, and since such a transition metal nitride is electrically conductive and the oxygen content in the transition metal nitride is controlled to be less than 20 atm%, this transition metal nitride Almost no silicon dioxide is produced by the reaction between oxygen and silicon in the metal nitride, and the small amount of silicon dioxide that is produced is gradually diffused into the grain boundaries of the crystalline metal oxide. The decrease in capacity is suppressed.

Further, when the insulating film of the capacitor portion is made of a crystalline metal oxide, if there is no defect such as oxygen deficiency in the crystalline metal oxide, the releasable film in the insulating film is formed.
The electric current mainly flows through the grain boundaries of the crystalline metal oxide, but in the present invention, the components used in the reaction preventive layer are diffused into the grain boundaries as described above.
It is possible to significantly reduce the peak current.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is an example in which the present invention is applied to a DRAM having a stack type capacitor as a first embodiment.
In Examples 4 to 14, Examples applied to a chip type thin film capacitor used as a bypass capacitor or the like are shown in Examples 5 to 14. Embodiment 1 FIGS. 1A to 1D are vertical sectional views showing a part of a manufacturing process of a DRAM of this embodiment. The manufacturing process of the DRAM will be described below with reference to FIG.

First, a p-type silicon substrate (1) having a specific resistance value of 10 Ω · cm and a (100) surface is selectively thermally oxidized to form an insulating film (2) to be an element isolation region. To form. Then, a thin thermal oxide film and n + are formed on the device region.
After forming the mold type polysilicon film, patterning is performed by a normal photolithography process to form a gate oxide film (3) and a gate electrode (4). After this,
Ion implantation is performed in a self-aligned manner in the device region using the gate electrode (4) as a mask to form a source and drain region (5) made of n-type silicon (FIG. 1A).

Next, an interlayer insulating film (6) made of SiO ₂ is formed on the entire surface by the CVD method, and a contact hole (7) is formed in a predetermined region by a normal photolithography process (FIG. 1 (b). )).

Next, after depositing n + type polysilicon on the entire surface by the CVD method, it is patterned into a desired shape by an ordinary photolithography process to form a lower electrode (8) of the capacitor section. Then, the surface of the n + -type polysilicon that is the lower electrode (8) is directly thermally nitrided in an ammonia gas atmosphere to form a reaction preventing layer (9) made of silicon nitride having a thickness of 10 Å. .. Further, after forming an insulating film (10) made of Ta ₂ O ₅ on the reaction prevention layer (9) made of silicon nitride by a CVD method,
Anneal at 700 ° C. for 30 minutes in a nitrogen atmosphere (FIG. 1C). In this insulating film (10), Ta ₂
It has been confirmed by X-ray diffraction that O ₅ is crystallized by the above-mentioned anneal.

Then, after depositing tungsten on the entire surface by the CVD method, patterning is performed by an ordinary photolithography process to form an upper electrode (1) on the insulating film (10).
By forming (1), a stack type capacitor corresponding to the capacitor section in the present invention was obtained (FIG. 1).
(D)). Thereafter, the wiring of the drive line, the passivation film, and the like were formed according to the usual DRAM manufacturing process, and the DRAM of this example was manufactured.

On the other hand, as a comparative example, a reaction preventive layer is provided between the lower electrode and the insulating film in the same manner except that silicon nitride is not formed by thermal nitridation of n + type polysilicon which is the lower electrode. An undeveloped DRAM was manufactured.

With respect to these DRAMs, an electric field was gradually applied between the upper electrode and the lower electrode, and the leak current at this time was measured. The results are shown in Figure 2. In FIG.
The solid line shows the leak current in the DRAM of this embodiment, and the broken line shows the leak current in the DRAM of the comparative example. As is apparent from FIG. 2, in the DRAM of this embodiment, by providing the reaction prevention layer, the leak current in the capacitor portion is remarkably reduced. In addition, it was confirmed that the capacitance of the capacitor part was also extremely small. Example 2

First, the surface of a p-type silicon substrate having a specific resistance value of 10 Ω · cm and a (100) surface is thermally oxidized to form an insulating film to be an element isolation region. Similarly, a gate oxide film, a gate electrode, a source,
Provide a drain region.

Further, an interlayer insulating film, a lower electrode, a reaction preventive layer made of silicon nitride, and an insulating film made of crystalline Ta ₂ O ₅ were sequentially formed by the same method as in Example 1, and then T
A reaction preventing layer made of tantalum nitride having a thickness of 50 angstrom is provided on an insulating film made of a ₂ O ₅ by a sputtering method in an atmosphere containing a small amount of oxygen. In addition,
The oxygen content in the tantalum nitride as measured by the gas fusion analysis method was 15 atm% or less.

Subsequently, p + type polysilicon is deposited on the entire surface by the CVD method, and then the ordinary photolithography-
By patterning in the process, an upper electrode was formed on the reaction preventive layer made of tantalum nitride to obtain a stack type capacitor corresponding to the capacitor portion in the present invention. Thereafter, the wiring of the drive line, the passivation film, and the like were formed according to the usual DRAM manufacturing process, and the DRAM of this example was manufactured.

When the leak current of the obtained DRAM was measured in the same manner as in Example 1, the electric field-current characteristics were almost the same as in Example 1, and even if polysilicon was used for the upper electrode, the insulating film was formed. It was confirmed that the increase of the leak current can be suppressed by providing the reaction preventive layer made of tantalum nitride between and. Example 3

First, the surface of a p-type silicon substrate having a specific resistance value of 10 Ω · cm and a (100) surface is thermally oxidized to form an insulating film serving as an element isolation region. Similarly, a gate oxide film, a gate electrode, a source,
Provide a drain region.

Next, an interlayer insulating film made of SiO ₂ is formed on the entire surface by the CVD method, and the ordinary photolithography-
A contact hole is formed in a predetermined region by a process.
Then, a thin titanium nitride layer is formed in the contact hole by a sputtering method, tungsten is deposited on the entire surface by a CVD method, and a desired shape is patterned by an ordinary photolithography process to form a capacitor portion. Of the lower electrode. Further, an insulating film made of Ta ₂ O ₅ is formed on the lower electrode by a sputtering method, Ta ₂ O ₅ is crystallized by the same annealing as in Example 1, and then the surface of this insulating film is covered with ammonia. Direct thermal nitriding is performed in a gas atmosphere to form a reaction preventing layer made of tantalum nitride having a thickness of 50 Å. The oxygen content in the tantalum nitride measured by the gas fusion analysis method is
It was 20 atm% or less.

Then, n + -type polysilicon is deposited on the entire surface by the CVD method, and then the ordinary photolithography-
By patterning in the process, an upper electrode was formed on the reaction preventive layer made of tantalum nitride to obtain a stack type capacitor corresponding to the capacitor portion in the present invention. After that, the wiring to be the drive line, the passivation film, etc. are formed in accordance with the usual DRAM manufacturing process,
The DRAM of this example was manufactured.

On the other hand, as a comparative example, a DRAM having no reaction prevention layer between the insulating film and the upper electrode was manufactured in exactly the same manner except that tantalum nitride was not formed by thermal nitriding of Ta ₂ O ₅ . ..

With respect to these DRAMs, an electric field was gradually applied between the upper electrode and the lower electrode, and the leak current at this time was measured. Results are shown in FIG. As is apparent from FIG. 3, in the DRAM of this embodiment, the leakage current in the capacitor portion is remarkably reduced by providing the reaction preventing layer made of tantalum nitride. In addition, it was confirmed that the capacitance of the capacitor part was also extremely small. Example 4

The same DRAM as in Example 1 except that a reaction preventing layer made of titanium nitride having a thickness of 50 angstrom is provided between the lower electrode and the insulating film, instead of the reaction preventing layer made of silicon nitride. Was manufactured. The reaction preventing layer made of titanium nitride was formed by forming a layer made of titanium oxide on the lower electrode by a CVD method and then directly thermally nitriding it in an ammonia gas atmosphere. The oxygen content in the titanium nitride measured by gas fusion analysis was 13 atm% or less.

When the leak current of the obtained DRAM was measured in the same manner as in Example 1, the electric field-current characteristics were almost the same as in Example 1, and a capacitor section with a small leak current was formed. Was confirmed. Example 5

FIG. 4 is a vertical cross-sectional view showing the chip type thin film capacitor of the present embodiment. In this embodiment, a nitride film is formed on the n-type silicon wafer to be the lower electrode (12) by the following process. Reaction prevention layer made of silicon (1
3), an insulating film (14) made of SrTiO ₃ , and Ti
The upper electrode (15) made of / Pt is formed, and a T electrode for contacting the lower electrode is formed on the back surface of the lower electrode.
An i / Pt film (16) was provided to manufacture the chip type thin film capacitor.

First, an n-type silicon wafer doped with As was exposed to ammonia gas at 1000 ° C. for 10 minutes to form a reaction preventive layer made of silicon nitride on the surface of the n-type silicon wafer. It was confirmed by Auger analysis that the thickness of the reaction preventive layer made of silicon nitride was 15 Å. Then, on this n-type silicon wafer, SrTiO 3 was formed by the RF magnetron sputtering method.
_An insulating film of ₃ was formed. The target is Sr.
It is a sintered body of TiO ₃ and the film forming condition is a substrate temperature of 400.
_{℃, Ar / O 2 (40sccm} / 10sccm) gas atmosphere, the gas pressure 0.58Pa, an RF power 400W, by adjusting the thickness by changing the deposition time, the thickness, respectively 1000,1500,2000, Four kinds of 2500 angstrom were obtained.

Next, Ti and Pt of 700 and 2000 angstroms were respectively deposited on the obtained insulating film by the sputtering method. Further, in order to make contact with the lower electrode, a Ti / Pt film was similarly deposited on the back surface of the n-type silicon wafer by 700 and 2000 angstroms, respectively. Further, Ti / Pt deposited on the insulating film was etched into a predetermined pattern by a photolithography process to form a 1 mm × 2 mm upper electrode. After this,
By dicing the n-type silicon wafer on which the insulating film, the upper electrode and the like as described above are formed, four types of chip type thin film capacitors of this example having a size of approximately 1 mm × 2 mm were manufactured.

In the chip type thin film capacitors, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, none of the generation of silicon dioxide was confirmed. Therefore, in the chip type thin film capacitor, the lower electrode silicon and SrT
It is considered that the increase in the leak current in the insulating film due to the reaction with iO ₃ is suppressed. Also SrTiO ₃
In the insulating film made of, a small amount of an amorphous compound was observed in the grain boundary of SrTiO ₃ in the vicinity of the reaction preventive layer made of silicon nitride, and the components in the reaction preventive layer were diffused into the grain boundary. It was confirmed that Furthermore, SrTiO
_The capacitance value and its frequency dependence were measured for the chip type thin film capacitor in which the thickness of the insulating film made of ₃ was 2000 angstrom. Results are shown in FIG. As shown in FIG. 5, this chip type thin film capacitor has a high capacitance value and excellent frequency characteristics.

On the other hand, as a comparative example, a reaction preventive layer is provided between the n-type silicon wafer as the lower electrode and the insulating film in the same manner except that silicon nitride is not formed on the surface of the n-type silicon wafer. An unchip type thin film capacitor was prepared. In this chip type thin film capacitor, a silicon dioxide layer having a thickness of about 50 Å was observed at the interface between the n-type silicon wafer and the insulating film by a cross-section transmission electron microscope. Further, the capacitance was 5 nF when the thickness of the insulating film was 2000 angstrom, and the capacitance was remarkably reduced due to the formation of the silicon dioxide layer as described above. Example 6

RTA (Rapid Thermal Anneal) is provided between the n-type silicon wafer which is the lower electrode and the insulating film.
Then, a reaction preventive layer made of silicon nitride having a thickness of about 6 angstrom is formed by the method, and the size of the upper electrode is 1 mm × 1.
In the same manner as in Example 5 except that the thickness was set to 1 mm, approximately 1 mm ×
A 1 mm chip type thin film capacitor was produced.

In this chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed with a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, in the chip type thin film capacitor, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. In the insulating film made of SrTiO _3, a small amount of amorphous compounds are observed in the vicinity of the reaction preventing layer made of silicon nitride in the grain boundaries of SrTiO _3, wherein in the component of the reaction-preventing layer in said grain boundary It was confirmed that it was diffused. Next, when the capacitance of the chip type thin film capacitor in which the thickness of the insulating film made of SrTiO ₃ is 2500 angstrom was measured, a sufficient value of about 7 nF was obtained. Further, FIG. 6 is a characteristic diagram showing the frequency characteristic of the capacitance of the chip type thin film capacitor, and this chip type thin film capacitor has excellent frequency characteristic as shown. Example 7

In this example, a chip type thin film capacitor of approximately 1 mm × 2 mm was prepared in exactly the same manner as in Example 5 except that the insulating film made of SrTiO ₃ was formed by the sol-gel method. In forming the insulating film made of SrTiO ₃ , after coating a mixed solution of titanium butoxide and strontium methoxyethoxide, 500
The process of heat treatment at ℃ was repeated 5 times, and the thickness of the insulating film was set to 2000 angstrom.

In the chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. Also Sr
In the insulating film made of TiO ₃ , a small amount of an amorphous compound was observed in the grain boundaries of SrTiO ₃ in the vicinity of the reaction preventive layer made of silicon nitride, and the components in the reaction preventive layer were diffused into the grain boundaries. It was confirmed that it was done. Further, the result of measuring the capacitance value and its frequency dependence of this chip type thin film capacitor is shown in FIG. As shown in FIG. 7, the chip type thin film capacitor of this example also has a high capacitance value and excellent frequency characteristics. Example 8

In this example, a chip type thin film capacitor of approximately 1 mm × 2 mm was prepared in exactly the same manner as in Example 5 except that the insulating film made of SrTiO ₃ was formed by the CVD method. In forming the insulating film made of SrTiO ₃ , Sr (C ₁₁ H ₁₉ O ₂ ) ₂ and Ti (C ₃
H ₇ O) ₄ as the source gas and the gas temperature is 22
0 ℃, 50 ℃, gas flow rate is 400sccm, 5 respectively
0 sccm and the substrate temperature of 600 ° C.
An insulating film having a film thickness of 000 angstrom was formed.

In the above chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. Also Sr
In the insulating film made of TiO ₃ , a small amount of an amorphous compound was observed in the grain boundaries of SrTiO ₃ in the vicinity of the reaction preventive layer made of silicon nitride, and the components in the reaction preventive layer were diffused into the grain boundaries. It was confirmed that it was done. Further, the result of measuring the capacitance value and its frequency dependence of this chip type thin film capacitor is shown in FIG. As shown in FIG. 8, the chip type thin film capacitor of this embodiment also has a high capacitance value and excellent frequency characteristics. Example 9

Instead of exposing the n-type silicon wafer to 1000 ° C. ammonia gas for 10 minutes to form a reaction preventive layer made of silicon nitride on the surface, it is exposed to 1000 ° C. methane gas for 10 minutes to prevent the reaction made of silicon carbide on the surface. Except for forming the layer, the procedure was exactly the same as in Example 5, except that the thickness was approximately 1 m.
An m × 2 mm chip type thin film capacitor was produced. The thickness of the reaction preventing layer made of silicon carbide is
It was confirmed by J.A. analysis that it was 13 angstroms.

In this chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed with a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, in the chip type thin film capacitor, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. In the insulating film made of SrTiO _3, a small amount of amorphous compound in the grain boundary of SrTiO ₃ in the vicinity of consisting of silicon carbide reaction preventing layer is observed, during said components of the reaction preventing layer is the grain boundary It was confirmed that it was diffused. Further, FIG. 9 shows the results of measuring the capacitance value and its frequency dependence with respect to a chip type thin film capacitor in which the insulating film made of SrTiO ₃ has a film thickness of 2000 angstroms. As shown in FIG.
The chip-type thin film capacitor of this embodiment also has a high capacitance value and excellent frequency characteristics. Example 10

In this example, a chip type thin film capacitor of approximately 1 mm × 2 mm was prepared in exactly the same manner as in Example 9 except that an insulating film made of SrTiO ₃ was formed by the sol-gel method. The insulating film was formed by the sol-gel method according to the process of Example 7, and the film thickness was set to Example 7.
And 2000 angstrom.

In the above chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. Also Sr
In the insulating film made of TiO ₃ , a small amount of an amorphous compound was observed in the grain boundary of SrTiO ₃ in the vicinity of the reaction preventive layer made of silicon carbide, and the components in the reaction preventive layer were diffused into the grain boundary. It was confirmed that it was done. Further, the results of measuring the capacitance value and its frequency dependence of this chip type thin film capacitor are shown in FIG. As shown in FIG. 10, a high capacitance value and excellent frequency characteristics are obtained even with the chip type thin film capacitor of this embodiment. Example 11

In this example, a chip type thin film capacitor of approximately 1 mm × 2 mm was produced in exactly the same manner as in Example 9 except that an insulating film made of SrTiO ₃ was formed by the CVD method. The insulating film was formed by the CVD method according to the process in Example 8, and the film thickness was set to 2000 angstroms as in Example 8.

In the above chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer which is the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. Also Sr
In the insulating film made of TiO ₃ , a small amount of an amorphous compound was observed in the grain boundary of SrTiO ₃ in the vicinity of the reaction preventive layer made of silicon carbide, and the components in the reaction preventive layer were diffused into the grain boundary. It was confirmed that it was done. Further, the result of measuring the capacitance value and its frequency dependence of this chip type thin film capacitor is shown in FIG. As shown in FIG. 11, the chip type thin film capacitor of this example also has a high capacitance value and excellent frequency characteristics. Example 12

Instead of exposing the n-type silicon wafer to ammonia gas at 1000 ° C. for 10 minutes to form a reaction preventive layer made of silicon nitride on the surface, the n-type silicon wafer is made of fluoride (CaF ₂ ) by a sputtering method. A chip type thin film capacitor of approximately 1 mm × 2 mm was prepared in exactly the same manner as in Example 5 except that the reaction preventive layer was formed.
The thickness of the reaction preventive layer made of this fluoride is
It was confirmed by J.A. analysis that the thickness was 15 angstroms.

In the chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, in the chip type thin film capacitor, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. In the case of an insulating film made of SrTiO ₃ , S is formed near the reaction preventive layer made of fluoride.
A small amount of amorphous compound was observed in the grain boundary of rTiO ₃ ,
It was confirmed that the components in the reaction prevention layer were diffused into the grain boundaries. Further, FIG. 12 shows the results of measuring the capacitance value and its frequency dependence for a chip type thin film capacitor in which the insulating film made of SrTiO ₃ has a film thickness of 2000 angstroms. As shown in FIG.
The chip-type thin film capacitor of this embodiment also has a high capacitance value and excellent frequency characteristics. In this example,
Although CaF ₂ was used as the fluoride, similar characteristics can be obtained by using LiF or the like. Example 13

In this example, a chip type thin film capacitor of approximately 1 mm × 2 mm was prepared in exactly the same manner as in Example 12 except that an insulating film made of SrTiO ₃ was formed by the sol-gel method. The insulating film was formed by the sol-gel method according to the process of Example 7, and the film thickness was 2000 angstroms as in Example 7.

In the chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. Also Sr
In the insulating film made of TiO ₃ , a small amount of an amorphous compound was observed in the grain boundary of SrTiO ₃ in the vicinity of the reaction preventive layer made of fluoride, and the components in the reaction preventive layer were diffused into the grain boundary. It was confirmed that it was done. Further, the results of measuring the capacitance value and its frequency dependence of this chip type thin film capacitor are shown in FIG. As shown in FIG. 13, the chip type thin film capacitor of this embodiment also has a high capacitance value and excellent frequency characteristics. Example 14

In this example, a chip type thin film capacitor of approximately 1 mm × 2 mm was prepared in exactly the same manner as in Example 12 except that an insulating film made of SrTiO ₃ was formed by the CVD method. The insulating film was formed by the CVD method according to the process in Example 8, and the film thickness was set to 2000 angstroms as in Example 8.

In the chip type thin film capacitor, when the vicinity of the surface of the n-type silicon wafer as the lower electrode was observed by a cross-section transmission electron microscope, generation of silicon dioxide was not confirmed at all. Therefore, it is considered that the increase of the leak current in the insulating film due to the reaction between the electrode made of silicon and SrTiO ₃ is suppressed. Also Sr
In the insulating film made of TiO ₃ , a small amount of an amorphous compound was observed in the grain boundaries of SrTiO ₃ in the vicinity of the reaction preventive layer made of fluoride, and the components in the reaction preventive layer were diffused into the grain boundaries. It was confirmed that it was done. Further, the results of measuring the capacitance value and its frequency dependence of this chip type thin film capacitor are shown in FIG. As shown in FIG. 14, the chip type thin film capacitor of this example also has a high capacitance value and excellent frequency characteristics.

[0059]

As described above in detail, the electronic component of the present invention has a capacitor portion having a large capacity and a small leak current, and its industrial value is great.

[Brief description of drawings]

1A to 1D are D showing an embodiment of the present invention.
FIG. 6 is a vertical cross-sectional view showing a part of the RAM manufacturing process.

FIG. 2 is an electric field-current characteristic diagram showing a leak current in a capacitor portion in a DRAM which is an embodiment of the present invention.

FIG. 3 is an electric field-current characteristic diagram showing a leak current in a capacitor portion in a DRAM which is another embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a chip type thin film capacitor manufactured according to an example of the present invention.

FIG. 5 is a frequency characteristic diagram of capacitance in a chip type thin film capacitor in which a reaction preventive layer made of silicon nitride is provided between a lower electrode and an insulating film.

FIG. 6 is a frequency characteristic diagram of capacitance in a chip type thin film capacitor in which a reaction prevention layer made of silicon nitride is provided between a lower electrode and an insulating film by an RTA method.

FIG. 7 is a frequency characteristic diagram of capacitance in another chip type thin film capacitor in which a reaction preventive layer made of silicon nitride is provided between a lower electrode and an insulating film.

FIG. 8 is a frequency characteristic diagram of capacitance in still another chip type thin film capacitor in which a reaction preventive layer made of silicon nitride is provided between a lower electrode and an insulating film.

FIG. 9 is a frequency characteristic diagram of capacitance in a chip type thin film capacitor in which a reaction preventive layer made of silicon carbide is provided between a lower electrode and an insulating film.

FIG. 10 is a frequency characteristic diagram of capacitance in another chip type thin film capacitor in which a reaction preventive layer made of silicon carbide is provided between a lower electrode and an insulating film.

FIG. 11 is a frequency characteristic diagram of capacitance in still another chip type thin film capacitor in which a reaction preventive layer made of silicon carbide is provided between a lower electrode and an insulating film.

FIG. 12 is a frequency characteristic diagram of capacitance in a chip type thin film capacitor in which a reaction preventive layer made of a fluoride is provided between a lower electrode and an insulating film.

FIG. 13 is a frequency characteristic diagram of capacitance in another chip type thin film capacitor in which a reaction preventive layer made of a fluoride is provided between a lower electrode and an insulating film.

FIG. 14 is a frequency characteristic diagram of capacitance in still another chip type thin film capacitor in which a reaction preventive layer made of a fluoride is provided between a lower electrode and an insulating film.

[Explanation of symbols]

 1 ... Silicon substrate, 8, 12 ... Lower electrode, 9, 13 ... Reaction prevention layer, 10, 14 ... Insulating film, 11, 15 ... Upper electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigehiko Saida 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Stock company Toshiba Research Institute

Claims (2)

[Claims] 1. In an electronic component having a capacitor section having a crystalline metal oxide as an insulating film, at least one of a pair of electrodes opposed to each other with the insulating film being made of silicon, and the electrode being made of silicon. At least one selected from the group consisting of silicon nitride, silicon carbide and fluoride is interposed between the insulating film and the insulating film. 2. An electronic component having a capacitor section using a crystalline metal oxide as an insulating film, at least one of a pair of electrodes facing each other with the insulating film being made of silicon, and the electrode being made of silicon. An electronic component, wherein a transition metal nitride containing less than 20 atm% oxygen is interposed between the insulating film and the insulating film.